Resin, resist composition and method for producing resist pattern

ABSTRACT

A resist composition contains: a resin having an acid-labile group, a resin having a structural unit represented by formula (I), an acid generator, and a solvent; 
     
       
         
         
             
             
         
       
     
     wherein R i41  represents a hydrogen atom or a methyl group, R i42  represents a C 1  to C 10  hydrocarbon group that may be substituted with a hydroxy group, a C 2  to C 7  acyl group or a hydrogen atom, R i43  in each occurrence independently represents a C 1  to C 6  alkyl group or a C 1  to C 6  alkoxy group, “p” represents an integer of 0 to 4, Z represents a divalent C 3  to C 20  hydrocarbon group having a group represented by formula (Ia), and a methylene group contained in the hydrocarbon group may be replaced by an oxygen atom, a sulfur atom or a carbonyl group, *—[(CH 2 ) w —O] r — (Ia): wherein “w” and “r” each independently represents an integer of 1 to 10, and * represent a bonding position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Application No. 2015-73002filed on Mar. 31, 2015. The entire disclosure of Japanese ApplicationNo. 2015-73002 is incorporated hereinto by reference.

BACKGROUND

1. Field of the Invention

The disclosure relates to a resin, a resist composition and a method forproducing resist pattern.

2. Related Art

In the mounting of the semiconductor chip being thin film and havingmulti-pin, the protruding electrodes of about 4 to 150 μm height, whichis connection terminals (bumps), are formed on the substrate (wafer) byphotolithography. As a method for forming such a connection terminal,JP2011-75864A1 mentions use of a resin having a structural unit derivedfrom p-hydroxystyrene for resist compositions.

SUMMARY

The present application provides the inventions as follow.

[1] A resist composition contains:

a resin having an acid-labile group,

a resin having a structural unit represented by formula (I),

an acid generator, and

a solvent:

wherein R^(i41) represents a hydrogen atom or a methyl group,

R^(i42) represents a C₂ to C₇ acyl group or a hydrogen atom, or a C₁ toC₁₀ hydrocarbon group in which a hydrogen atom can be replaced by ahydroxy group,

R^(i43) in each occurrence independently represents a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group,

“p” represents an integer of 0 to 4,

Z represents a divalent C₃ to C₂₀ hydrocarbon group having a grouprepresented by formula (Ia), and a methylene group contained in thehydrocarbon group may be replaced by an oxygen atom, a sulfur atom or acarbonyl group:

*—[(CH₂)_(w)—O]_(r)—  (Ia)

wherein “w” and “r” each independently represents an integer of 1 to 10,and

* represent a bonding position, provided that R^(i42) represents a C₂ toC₇ acyl group when “w” represents 1.

[2] The resist composition according to [1] wherein

the structural unit represented by formula (I) is a structural unitrepresented by formula (I-1) or formula (I-2):

wherein R^(i41) represents a hydrogen atom or a methyl group,

R^(i42) represents a C₁ to C₁₀ hydrocarbon group that may be substitutedwith a hydroxy group, a C₂ to C₇ acyl group or a hydrogen atom,

R^(i43) in each occurrence independently represents a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group,

“p” represents an integer of 0 to 4,

R^(i44) represents a C₁ to C₁₀ hydrocarbon group,

“r” represents an integer of 1 to 10, and

R⁴⁵ represents a C₁ to C₁₀ hydrocarbon group that may be substitutedwith a hydroxy group, a C₂ to C₇ acyl group or a hydrogen atom.

[3] The resist composition according to [1] or [2] wherein

the resin having an acid-labile group is a resin having a structuralunit represented by formula (a1-2):

wherein R^(a5) represents a hydrogen atom or a methyl group,

R^(a1′) and R^(a2′) each independently represent a hydrogen atom or a C₁to C₁₂ hydrocarbon group, R^(a33′) represents a C₁ to C₂₀ hydrocarbongroup, or R^(a1′) represents a hydrogen atom or a C₁ to C₁₂ hydrocarbongroup, and R^(a2′) and R^(a33′) are bonded together with a carbon atomand an oxygen atom bonded thereto to form a divalent heterocyclic grouphaving 2 to 20 carbon atoms, and a methylene group contained in thehydrocarbon group represented by R^(a1′) and R^(a2′) or the divalentheterocyclic group may be replaced by an oxygen atom or a sulfur atom,

R^(a6) in each occurrence independently represents a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group, and

“mz” represents an integer of 0 to 4.

[4] The resist composition according to claim any one of [1] to [3]wherein

the acid generator is a compound having a group represented by formula(B1):

wherein R^(b1) represents a C₁ to C₁₈ hydrocarbon group in which ahydrogen atom may have a fluorine atom and in which a methylene groupmay be replaced by an oxygen atom or a carbonyl group.

[5] A method for producing a resist pattern comprising steps (1) to (4);

(1) applying the resist composition according to any one of [1] to [4]onto a substrate;

(2) drying the applied composition to form a composition layer;

(3) exposing the composition layer; and

(4) developing the exposed composition layer.

[6] A resin has a structural unit represented by formula (I-2):

wherein R^(i41) represents a hydrogen atom or a methyl group,

R^(i43) in each occurrence independently represents a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group,

“p” represents an integer of 0 to 4,

R^(i44) represents a C₁ to C₁₀ hydrocarbon group,

“r” represents an integer of 1 to 10, and

R^(i45) represents a C₁ to C₁₀ hydrocarbon group that may be substitutedwith a hydroxy group, a C₂ to C₇ acyl group or a hydrogen atom.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1(a) illustrates an excellent cross-sectional view of a photoresistpattern which has substantially rectangle shape at its top and bottomportions, and

FIG. 1(b) illustrates a cross-sectional view of a photoresist patternwhich has a round shape at its bottom portion.

DETAILED DESCRIPTION OF DISCLOSURE

In the specification, the term “(meth)acrylic monomer” means a monomerhaving a structure of “CH₂═CH—CO—” or “CH₂═C(CH₃)—CO—”, as well as“(meth)acrylate” and “(meth)acrylic acid” mean “an acrylate ormethacrylate” and “an acrylic acid or methacrylic acid,” respectively.The group described herein, which can take both the linear structure andbranch structure, may be either. When stereo isomers exist, it includesall stereoisomers. The indefinite articles “a” and “an” are taken as thesame meaning as “one or more”.

The term “solid components” means components other than solvents in aresist composition.

<Resist Composition>

The resist composition according to the disclosure contains

a resin having an acid-labile group (which is sometimes referred to as“resin (A1)”),

a resin having a structural unit represented by formula (I) (which issometimes referred to as “resin (A3)”),

an acid generator (which is sometimes referred to as “acid generator(B)”), and

a solvent (which is sometimes referred to as “solvent (D)”).

The resist composition of the disclosure may further contain a resindifferent from the resin (A1), such as an alkali-soluble resin (which issometimes referred to as “resin (A2)”), a quencher (which is sometimesreferred to as “quencher (C)”) and an adhesion improver (which issometimes referred to as “adhesion improver (E)”), or the like. Thestructural unit represented by formula (I) is sometimes referred to as“structural unit (I)”.

<Resin (A1)>

The resin (A1) has the structural unit having an acid-labile group(which is sometimes referred to as “structural unit (a1)”).

The “acid-labile group” means a group having a leaving group which isdetached by contacting with an acid resulting in forming a hydrophilicgroup such as a hydroxy or carboxy group. In other words, the“acid-labile group” means ones solubility of the structural unit havingthe acid-labile group into an alkaline aqueous solution is increased bythe action of an acid. Therefore, solubility into an alkaline aqueoussolution of the resin (A1) increases by the action of the acid.

The “solubility in an alkaline aqueous solution is increased by theaction of an acid” means to increase the solubility in an alkalineaqueous solution by contact with an acid. The resin is preferably aresin which is insoluble or poorly soluble in an alkali aqueous solutionbefore contact with the acid, and becomes soluble in an alkaline aqueoussolution after contact with the acid.

The resin (A1) may further have a structural unit having no acid-labilegroup (which is sometimes referred to as “structural unit (a2)”) and/oranother type of known structural unit in the art in addition to thestructural unit having an acid-labile group. Herein, the resin (A1) doesnot have the structural unit represented by formula (I).

Examples of the acid-labile group include a group represented by theformula (1) and the formula (2).

In the formula (1), R^(a1), R^(a2) and R^(a3) each independentlyrepresent a C₁ to C₈ alkyl group, a C₃ to C₂₀ alicyclic hydrocarbongroup, or R^(a1) and R^(a2) may be bonded together with a carbon atombonded thereto to form a C₂ to C₂₀ divalent hydrocarbon group and R^(a3)represents a C₁ to C₈ alkyl group or a C₃ to C₂₀ alicyclic hydrocarbongroup, and * represents a binding position.

In the formula (2), R^(a1′) and R^(a2′) each independently represent ahydrogen atom or a C₁ to C₁₂ hydrocarbon group, R^(a3′) represents a C₁to C₂₀ hydrocarbon group, or R^(a1′) at represents a hydrogen atom or aC₁ to C₁₂ hydrocarbon group, and R^(a2′) and R^(a3′) are bonded togetherwith a carbon atom and an oxygen atom bonded thereto to form a divalentheterocyclic group having 2 to 20 carbon atoms, and a methylene groupcontained in the hydrocarbon group or the divalent heterocyclic groupmay be replaced by an oxygen atom or a sulfur atom, and * represents abinding position.

Examples of the alkyl group for R^(a1) to R^(a3) include methyl, ethyl,propyl, butyl, pentyl, hexyl, heptyl and octyl groups.

The alicyclic hydrocarbon group for R^(a1) to R^(a3) may be a monocyclicor polycyclic group. Examples of the monocyclic alicyclic hydrocarbongroup include a cycloalkyl group such as cyclopentyl, cyclohexyl,cycloheptyl and cyclooctyl groups. Examples of the polycyclic alicyclichydrocarbon group include decahydronaphthyl, adamantyl, norbornyl, andthe following groups.

In the formula, * represents a binding position.

The alicyclic hydrocarbon group for R^(a1) to R^(a3) preferably is a C₃to C₁₆ alicyclic hydrocarbon group.

When R^(a1) and R^(a2) is bonded together to form a divalent hydrocarbongroup, examples of the group —C(R^(a1))(R^(a2))(R^(a3)) include thefollowing groups. The divalent hydrocarbon group is preferably a C₃ toC₁₂ alicyclic hydrocarbon group. In each of the formulae, * represent abinding position to —O—.

Specific examples of the group represented by the formula (1) include,for example, an alkoxycarbonyl group (a group in which R^(a1) to R^(a3)are alkyl groups, preferably tert-butoxycarbonyl group, in the formula(1)),

1-alkylcyclopentane-1-yloxycarbonyl group and1-alkylcyclohexane-1-yloxycarbonyl group (a group in which R^(a1) andR^(a2) form a cyclopentyl or a cyclohexyl group, and R^(a3) is an alkylgroup, in the formula (1)), and

1-(cyclopentane-1-yl)-1-alkylalkoxycarbonyl group and1-(cyclohexane-1-yl)-1-alkylalkoxycarbonyl group (a group in whichR^(a1) and R^(a2) are an alkyl group, and R^(a3) a cyclopentyl or acyclohexyl group, in the formula (1)).

The hydrocarbon group for R^(a1′) to R^(a3′) in formula (2) may be analkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbongroup and a combination thereof.

Examples of the alkyl group include methyl, ethyl, propyl, butyl,pentyl, hexyl, heptyl, octyl, decyl and dodecyl groups.

Examples of the alicyclic hydrocarbon group include a cycloalkyl groupsuch as cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl groups; anda polycyclic alicyclic hydrocarbon group such as decahydronaphthyl,adamantyl, norbornyl, and the following groups.

Examples of the aromatic hydrocarbon group include an aryl group such asphenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl,p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl,phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.

Examples of groups combining the alkyl group and the alicyclichydrocarbon group include methylcyclohexyl, dimethylcyclohexyl,methylnorbornyl, isobonyl, 2-alkyladamanane-2-yl and 1-(adamantane-1-yl)alkane-1-yl groups.

Examples of groups combining the aromatic hydrocarbon group and thealkyl group include aralkyl group such as benzyl, phenethyl,phenylpropyl, naphthylmethyl and naphthylethyl groups.

Examples of the divalent heterocyclic group formed by binding withR^(a2′) and R^(a3′) with a carbon atom and an oxygen atom bonded theretoinclude the following groups. * represent a binding position.

In each formula, R^(a1′) is preferably a hydrogen atom.

Specific examples of the group represented by the formula (2) includethe following groups.

In each of the formulae, * represent a binding position.

<Structural Unit (a1)>

The monomer which derives the structural unit (a1) is preferably amonomer which has an acid-labile group and an ethylene unsaturated bond,and is more preferably a monomer having a group represented by theformula (1) and/or (2) and a ethylene unsaturated bond, provided thatthe monomers is those other than the monomers which derives thestructural unit (a1).

The resin (A1) may have one kind of the structural unit (a1-1) or two ormore of them.

Examples of the structural units (a1) preferably include the structuralunits represented by formula (a1-1) and formula (a1-2), these aresometimes referred to as the “structural unit (a1-1)” and “structuralunit (a1-2)”.

In the formulae, R^(a1), R^(a2), R^(a3), R^(a1′) and R^(a2′) are asdefined above,

R^(a33′) represents a C₁ to C₂₀ hydrocarbon group or R^(a2′) andR^(a33′) are bonded together with a carbon atom and an oxygen atombonded thereto to form a divalent heterocyclic group having 2 to 20carbon atoms,

R^(a4) and R^(a5) each independently represent a hydrogen atom or amethyl group,

R^(a6) in each occurrence independently represents a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group, and

“mz” represents an integer of 0 to 4.

Examples of the hydrocarbon group for R^(a33′) include the same groupsas those of R^(a3′).

In the formula (a1-1), R^(a4) is preferably a hydrogen atom.

In the formula (a1-2), R^(a1′) is preferably a hydrogen atom.

R^(a2′) is preferably a C₁ to C₁₂ hydrocarbon group, and more preferablya methyl group or an ethyl group.

The hydrocarbon group of R^(a3′) is preferably a C₁ to C₁₈ alkyl group,a C₃ to C₁₈ alicyclic hydrocarbon group, a C₆ to C₁₈ aromatichydrocarbon group or a combination thereof, and more preferably a C₁ toC₁₈ alkyl group, a C₃ to C₁₈ alicyclic hydrocarbon group or a C₇ to C₁₈aralkyl group. The alkyl group and the alicyclic group is preferablyunsubstituted. When the aromatic hydrocarbon group has been substituted,the substituent is preferably a C₆ to C₁₀ aryloxy group.

R^(a5) is preferably a hydrogen atom.

R^(a6) is preferably a C₁ to C₄ alkoxy group, more preferably a methoxygroup or an ethoxy group, and still more preferably a methoxy group.

“mz” is preferably 0 or 1, and more preferably 0.

Examples of the structural unit represented by formula (a1-1) includethose represented by formulae (a1-1-1) to (a1-1-17).

Examples of the monomers which derive the structural unit (a1-2) includethose represented by formulae (a1-2-1) to (a1-2-14).

Examples of the monomers include monomers in which a methyl groupcorresponding to R^(a4) and R^(a5) has been replaced by a hydrogen atom.

Among them, the structural units derived from the monomers representedby formulae (a1-2-2), (a1-2-3), (a1-2-4), (a1-2-9) and (a1-2-14) arepreferred, and the structural units derived from the monomersrepresented by formulae (a1-2-2), (a1-2-3), (a1-2-4) and (a1-2-9) aremore preferred.

The resin (A1) having an acid-labile group is preferably a resin havingthe structural unit (a1-2).

When the resin (A1) has the structural unit(s) represented by formula(a1-1) and/or formula (a1-2), the total content of these is preferably 5to 60% by mole, more preferably 10 to 55% by mole, still more preferably15 to 50% by mole, and particularly preferably 20 to 45% by mole withrespect to the total structural units (100% by mole) of the resin (A1).

<Structural Unit (a2)>

The resin (A1) may have one kind of the structural unit (a2), or two ormore them.

Examples of the structural unit (a2) include structural unitsrepresented by formulae (a2-1), (a2-2) and (a2-3), these are sometimesreferred to as the “structural unit (a2-1)”, “structural unit (a2-2)”and “structural unit (a2-3)”.

In the formulae, R^(a7), R^(a8) and R^(a9) each independently representa hydrogen atom or a methyl group,

R^(a10) in each occurrence independently represents a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group,

m′ represents an integer of 0 to 4,

R^(a11) represents a hydrogen atom, a C₁ to C₁₀ primary or secondaryhydrocarbon group,

R^(a12) represents a C₁ to C₆ primary or secondary alkyl group,

L^(a1) represents a C₂ to C₆ alkanediyl group where the carbon atombonding to an oxygen atom is a primary or secondary carbon atom, and

n represents an integer of 1 to 30.

Examples of the alkyl group for R^(a10) and R^(a12) include methyl,ethyl, propyl, butyl, pentyl and hexyl groups.

Examples of the alkoxy group for R^(a10) include methoxy, ethoxy,propoxy, butoxy, pentyloxy and hexyloxy groups.

The hydrocarbon group for R^(a11) may be an alkyl group, an alicyclichydrocarbon group, an aromatic hydrocarbon group or a combinationthereof.

Examples of the alkyl group include methyl, ethyl, propyl, butyl,pentyl, hexyl, heptyl, octyl, nonyl and decyl groups.

The alicyclic hydrocarbon group may include a monocyclic and polycyclicgroups.

Examples of the monocyclic alicyclic hydrocarbon group include acycloalkyl group such as cyclopentyl, cyclohexyl, cycloheptyl andcyclooctyl groups.

Examples of the polycyclic alicyclic hydrocarbon group include adecahydronaphtyl, adamantyl and norbornyl groups as well as thefollowing groups. In each of the formulae, * represents a bindingposition.

Examples of groups combining the alkyl group and the alicyclichydrocarbon group include methylcyclohexyl, dimethylcyclohexyl,methylnorbornyl, cyclohexylmethyl, adamantylmethyl and norbornyletylgroups.

Examples of the aromatic hydrocarbon group include phenyl and naphthylgroups.

Examples of groups combining the alkyl group and the aromatichydrocarbon group include an aralkyl group such as benzyl group.

Examples of the alkanediyl group for L^(a1) include linear alkanediylgroups such as ethylene, propane-1,3-diyl, propane-1,2-diyl,butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, ethane-1,1-diyl,propane-1,1-diyl and propane-2,2-diyl groups; and branched alkanediylgroups such as propane-1,2-diyl, pentane-2,4-diyl,2-methylpropane-1,3-diyl, pentane-1,4-diyl and 2-methylbutane-1,4-diylgroups.

R^(a7) preferably represents a hydrogen atom.

R^(a8) and R^(a9) independently are preferably a methyl group.

R^(a10) is preferably a C₁ to C₄ alkoxy group, more preferably a methoxygroup or an ethoxy group, and still more preferably a methoxy group.

m′ represents preferably 0 or 1, more preferably 0.

R^(a11) represents preferably a C₁ to C₆ primary or secondary alkylgroup.

L^(a1) represents preferably a C₂ to C₄ alkanediyl group such asethane-1,2-diyl, propane-1,3-diyl, propane-1,2-diyl and butane-1,4-diylgroups, more preferably an ethane-1,2-diyl group.

n represents preferably an integer of 1 to 10.

R^(a12) represents preferably a C₁ to C₃ primary or secondary alkylgroup.

Examples of the structural unit represented by formula (a2-1) preferablyinclude those represented by formulae (a2-1-1), (a2-1-2), (a2-1-3) and(a2-1-4). The monomer which derives the structural unit (a1) ispreferably monomers described in JP2010-204634A1.

Examples of the monomers which derive the structural units representedby formula (a2-2) include alkyl(meth)acrylates such asmethyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate,butyl(meth)acrylate and hexyl(meth)acrylate;

cycloalkyl(meth)acrylates such as cyclopentyl(meth)acrylate andcyclohexyl(meth)acrylate;

polycyclic(meth)acrylates such as adamantyl(meth)acrylate, and

aryl(meth)acrylates such as phenyl(meth)acrylate andbenzyl(meth)acrylate.

Examples of the monomers which derive the structural units representedby formula (a2-3) include (meth)acrylates such as ethylene glycolmonomethyl ether(meth)acrylate, ethylene glycol monoethylether(meth)acrylate, ethylene glycol monopropyl ether(meth)acrylate,ethylene glycol monobutyl ether(meth)acrylate, diethylene glycolmonomethyl ether(meth)acrylate, triethylene glycol monomethylether(meth)acrylate, tetraethylene glycol monomethylether(meth)acrylate, pentaethylene glycol monomethylether(meth)acrylate, hexaethylene glycol monomethyl ether(meth)acrylate,nonaethylene glycol monomethyl ether(meth)acrylate, and octaethyleneglycol monomethyl ether(meth)acrylate.

Further, examples of the monomers which derive the structural unitsrepresented by formula (a2) include acrylic acid, methacrylic acid,crotonic acid, 2-hydroxyethyl(meth)acrylate,2-hydroxypropyl(meth)acrylate, styrene, α-methylstyrene,4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene and4-isopropoxystyrene.

Examples of the structural unit (a2) may include a structural unitrepresented by formula (a2-4). The structural unit is sometimes referredto as “structural unit (a2-4)”.

In the formula, R^(a13) represents a hydrogen atom or a methyl group,

R^(a14) in each occurrence independently represent a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group,

R^(a15) in each occurrence independently represent a primary or asecondary C₁ to C₁₂ hydrocarbon group where a methylene group may bereplaced by an oxygen atom or a carbonyl group, provided that themethylene group bonding to an oxygen atom may not be replaced by anoxygen,

m″ represents an integer of 0 to 4, and

m′″ represents an integer of 0 to 4,

provided that the total number of m″ and m′″ is 5 or less.

The hydrocarbon group for R^(a15) is a group in which the carbon atombonding to an oxygen atom is not a tertiary carbon atom, that is, thecarbon atom bonding to an oxygen atom has at least one atom other thanthe carbon atom such as a hydrogen atom.

The structural unit represented by formula (a2-4) does not include thestructural unit (I) and the structural unit (a1-2).

Examples of the alkyl group and the alkoxy group for R^(a14) are thesame examples as the group described in R^(a10).

Examples of the hydrocarbon group for R^(a15) are the same examples asthe group described in R^(a11).

Among them, R^(a15) is preferably a C₁ to C₅ liner or branched alkylgroup, a C₅ to C₁₀ alicyclic hydrocarbon group and phenyl groups as wellas a combination thereof, or these groups where a carbon atom bonding toan oxygen atom in these groups may be replaced by a carbonyl group.

Examples of the structural unit (a2-4) include the following ones.

Examples of the structural unit (a2-4) include the structural unitsrepresented by the above formulae in which a hydrogen atom correspondingto R^(a13) has been replaced by a methyl group.

When the resin (A1) has the structural units (a2-1), (a2-2), (a2-3) and(a2-4), the total content of these is preferably 1 to 30% by mole, morepreferably 1 to 25% by mole, still more preferably 5 to 25% by mole, andparticularly preferably 5 to 20% by mole with respect to the totalstructural units (100% by mole) of the resin (A1).

When the resin (A1) has the structural unit (a2), the mole ratio of thestructural unit (a1): the structural unit (a2) is preferably 10:90 to80:20, more preferably 15:85 to 60:40, and still more preferably 15:85to 45:55.

Examples of combinations of the structural units in the resin (A1)include the following ones.

Examples of the structural units include structural units in which ahydrogen atom corresponding to R^(a5) has been replaced by a methylgroup, or a methyl group corresponding to R^(a5) has been replaced by ahydrogen atom. The resin may have a structural units having a hydrogenatom and a structural units having a methyl group as R^(a5).

The resin (A1) is preferably a resin having the structural unit (a1) andthe structural unit (a2), more preferably the structural units (a1-1)and/or (a1-2) and the structural unit (a2).

The resin (A1) may be a resin obtained by reacting a resin which has oneor both of a carboxy group and a phenolic hydroxyl group at its sidechain with a compound which has at least two vinyloxy groups, which issometimes referred to as “resin (A1b)”.

The resin (A1b) is preferably a resin obtained by reacting a resin whichhas a phenolic hydroxyl group with a compound which has at least twovinyloxy groups. Such resin can be produced by reacting a resin whichhas the structural unit (a1-2) with the compound which has at least twovinyloxy groups. A novolak resin described below can be used as theresin having a phenolic hydroxyl group, and the resin (A1b) may beproduced by reacting the above described novolak resin with the compoundwhich has at least two vinyloxy groups. The resin (A1b) may be a resinobtained by reacting the compound which has at least two vinyloxy groupswith a resin mixture containing a novolak resin and a resin having thestructural unit (a1-2). Further, the resin (A1b) may be a combination ofa resin which is obtained by reacting a resin having the structural unit(a1-2) with the above described the compound having at least twovinyloxy groups, with a resin which is obtained by reacting the novolakresin with the above described the compound having at least two vinyloxygroups.

In the synthesis of the resin (A1b), the mole ratio of the resin havinga phenolic hydroxyl group and a carboxyl group: the compound having atleast two vinyloxy groups may be 60 to 99:40 to 1, and preferably 70 to95:30 to 5.

Specific examples of the resin (A1b) include the resins described inJP2008-134515A1 and JP 2008-46594A1.

Examples of the compound having at least two vinyloxy groups include1,4-cyclohexanedimethanoldivinylether and ethyleneglycoldivinylether.

When the resin (A1b) contains the novolak resin as starting materials,the content thereof is 30 to 70% by mass with respect to the total massof the resin (A1b).

The resin (A1) can be produced by polymerizing the above-mentionedmonomers in a known manner such as radical polymerization.

The average weight molecule weight of the resin (A1) is preferably 8,000or more, more preferably 10,000 or more, and preferably 600,000 or less,more preferably 500,000 or less, still more preferably 300,000 or less,further more preferably 100,000 or less. In the present specification,the weight average molecular weight is a value determined by gelpermeation chromatography using polystyrene as the standard product. Thedetailed condition of this analysis is described in Examples.

The content of the resin (A1) in the resist composition is preferably10% by mass or more, and more preferably 15% by mass or more, andpreferably 95% by mass or less, and more preferably 85% by mass or lesswith respect to the total amount of solid components of the resistcomposition.

<Resin (A3)>

The resin (A3) is a resin having a structural unit represented byformula (I):

wherein R^(i41) represents a hydrogen atom or a methyl group,

R^(i42) represents a C₂ to C₇ acyl group, a hydrogen atom or a C₁ to C₁₀hydrocarbon group in which a hydrogen atom may be replaced by a hydroxygroup,

R^(i43) in each occurrence independently represents a C₁ to C₆ alkylgroup or a C₁ to C₆ alkoxy group,

“p” represents an integer of 0 to 4,

Z represents a divalent C₃ to C₂₀ hydrocarbon group having a grouprepresented by formula (Ia), and a methylene group contained in thehydrocarbon group may be replaced by an oxygen atom, a sulfur atom or acarbonyl group:

*—[(CH₂)_(w)—O]_(r)—  (Ia)

wherein “w” and “r” each independently represents an integer of 1 to 10,and

* represent a bonding position, provided that R^(i42) represents a C₂ toC₇ acyl group when “w” represents 1.

The hydrocarbon group may be an alkyl group, an alicyclic hydrocarbongroup, an aromatic hydrocarbon group and a combination thereof.

Examples of the alkyl group include methyl, ethyl, propyl, butyl,pentyl, hexyl, heptyl and octyl groups.

The alicyclic hydrocarbon group may be monocyclic or polycyclic group.Examples of the monocyclic alicyclic hydrocarbon group include acycloalkyl group such as cyclopentyl, cyclohexyl, cycloheptyl andcyclooctyl groups. Examples of the polycyclic alicyclic hydrocarbongroup include decahydronaphthyl and norbornyl.

Examples of groups combining the alkyl group and the alicyclichydrocarbon group include methylcyclohexyl, dimethylcyclohexyl,methylnorbornyl, methyladamantly, cyclohexylmethyl,methylcyclohexylmethyl, and norbornylmethyl groups.

Examples of the aromatic hydrocarbon group include an aryl group such asphenyl, naphthyl, p-methylphenyl, p-tert-butylphenyl, 2,6-diethyl phenyland 2-methyl-6-ethylphenyl groups.

Examples of the acyl group include acetyl, propionyl and butyryl groups.

Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy and tert-butoxy groups.

Examples of the divalent hydrocarbon group include an alkylene group, adivalent alicyclic hydrocarbon group, a divalent aromatic hydrocarbongroup and a combination thereof as long as it has *—[(CH₂)_(w)—O]_(r).The methylene group contained in the divalent hydrocarbon group may bereplaced by an oxygen atom, a sulfur atom or a carbonyl group. Here, *represent a bonding position to an oxygen atom, “w” and “r” eachindependently represents an integer of 1 to 10.

“w” is preferably an integer of 2 to 10, and more preferably 2 to 5.Among them, *—[(CH₂)_(w)—O]r is preferably *—[(CH₂)₂—O]_(r)— and*—[(CH₂)₃—O]_(r)—, and more preferably *—[(CH₂)₂—O]_(r)—. “r” ispreferably an integer of 2 to 10, and more preferably 2 to 5.

Specific examples of Z include the following ones. * represent a bondingposition to an oxygen atom, and ** represent a bonding position toR^(i42).

The structural unit represented by formula (I) is preferably structuralunits represented by formula (I-1) or formula (I-2):

wherein R^(i41), R^(i42), R^(i43), “p” and “r” are as defined above,

R^(i44) represents a C₁ to C₁₀ hydrocarbon group,

R^(i45) represents a C₂ to C₇ acyl group.

Examples of the hydrocarbon group for R^(i44) are the same examples asthe group described for R^(i42).

Examples of R^(i45) are the same examples as the acyl group describedfor R^(i42).

Examples of the structural units (I) include the following ones.

Examples of the structural unit include the structural units representedby the above formulae in which a hydrogen atom corresponding to R^(i41)has been replaced by a methyl group.

<Method for Producing the Structural Unit (I)>

The structural unit (I) and a resin having thereof can be produced by amethod as described below.

A monomer which derives the structural unit (I-2) can be obtained byreacting a compound represented by the formula (I-2a) with a compoundrepresented by the formula (I-2b) in presence of a catalyst in asolvent.

Preferred examples of the solvent include ethyl acetate and methylisobutyl ketone.

Preferred examples of the catalyst include the acidic catalyst such asp-toluene sulfonic acid and oxalic acid.

In the formulae, R^(i41), R^(i43), R^(i44), R^(i45), “p” and “r” are asdefined above.

The reaction can be conducted at temperature of preferably 10 to 150° C.for 0.1 to 18 hours, and more preferably 10 to 120° C. for 0.5 to 12hours.

Examples of the compound (I-2b) include a compound represented byformula (I-2b′), which can be obtained by protecting a hydroxy group ofa compound represented by the formula (I-2c).

The compounds represented by formula (I-2c) and formula (I-2d) areavailable on the market.

The resin (A3) may further have a structural unit other than thestructural unit represented by formula (I). Examples of such structuralunit include the structural unit (a1) described above, the structuralunit (a2), and another structural unit known in the art.

When the resin (A3) has the structural unit (a1), the content thereof ispreferably 1 to 50% by mole, more preferably 5 to 45% by mole, and stillmore preferably 5 to 40% by mole, with respect to the total structuralunits (100% by mole) of the resin (A3).

When the resin (A3) has the structural unit (a2), the content thereof ispreferably 1 to 50% by mole, more preferably 5 to 45% by mole, stillmore preferably 5 to 40% by mole, and further still more preferably 5 to35% by mole, with respect to the total structural units (100% by mole)of the resin (A3).

The total content of the resin (A3) is preferably 3% by mass or more,and more preferably 5% by mass or more, preferably 50% by mass or less,and more preferably 40% by mass or less, with respect to the total resincontent of the resist composition.

<Resin (A2)>

The resin (A2), that is the alkaline-soluble resin, means a resin whichhas an acid group and soluble in an alkaline developer. The acid groupincludes a carboxy group, a sulfo group or a phenolic-hydroxy group.

The alkaline-soluble resin includes known resins in the art such as anovolak resin, a resin having polymerization unit derived from ahydroxystylene which has the structural units (a2-1) and no structuralunit (a1), a resin having polymerization unit derived from a(meth)acrylic acid and a polyalkylene glycol. The novolak resin ispreferred. These may be used as a single resin or as a combination oftwo or more resins.

The novolak resin is a resin obtained by condensation of an aromatichydrocarbon having a phenolic hydroxyl group (which is sometimesreferred to as “phenolic compound”) with an aldehyde in the presence ofan acidic catalyst.

Examples of the phenolic compound include phenol, o-cresol, m-cresol orp-cresol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol,2,3,5-trimethylphenol, 2-tert-butylphenol, 3-tert-butylphenol,4-tert-butylphenol, 2-tert-butyl-4-methylphenol,2-tert-butyl-5-methylphenol, 2-methylresorcinol, 4-methylresorcinol,5-methylresorcinol, 2-methoxyphenol, 3-methoxyphenol, 4-methoxyphenol,2,3-dimethoxyphenol, 2,5-dimethoxyphenol, 3,5-dimethoxyphenol,2-methoxyresorcinol, 4-tert-butylcatechol, 2-ethylphenol, 3-ethylphenol,4-ethylphenol, 2,5-diethylphenol, 3,5-diethylphenol,2,3,5-triethylphenol, 2-naphthol, 1,3-dihydroxynaphthalene,1,5-dihydroxynaphthalene, 1,7-dihydroxynaphthalene and a polyhydroxytriphenylmethane compound which can be obtained by condensation ofxylenol and hydroxybenzaldehyde. These may be used as a single compoundor as a combination of two or more compounds.

Among them, the phenolic compound is preferably o-cresol, m-cresol,p-cresol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol,2,3,5-trimethylphenol, 2-t-butylphenol, 3-t-butylphenol,4-t-butylphenol, 2-t-butyl-4-methylphenol and 2-t-butyl-5-methylphenol.

Examples of the aldehyde include aliphatic aldehydes such asformaldehyde, acetaldehyde, propionaldehyde, n-butylaldehyde,isobutylaldehyde, acrolein and croton aldehyde; alicyclic aldehydes suchas cyclohexanealdehyde, cyclopentanealdehyde and furylacrolein; aromaticaldehydes such as furfural, benzaldehyde, o-, m- orp-methylbenzaldehyde, p-ethylbenzaldehyde, 2,4-, 2,5-, 3,4- or3,5-dimethylbenzaldehyde and o-, m- or p-hydroxybenzaldehyde; andaromatic aliphatic aldehydes such as phenylacetaldehyde andcinnamaldehyde. These may be used as a single compound or as acombination of two or more compounds.

Among them, formaldehyde is preferred in view of easy industrialavailability.

Examples of the catalyst for condensation includes inorganic acids suchas hydrochloric acid, sulfuric acid, perchloric acid and phosphoricacid; organic acid such as formic acid, acetic acid, oxalic acid,trichloroacetic acid and p-toluenesulfonic acid; divalent metal saltssuch as zinc acetate, zinc chloride and magnesium acetate. These may beused as a single compound or as a combination of two or more compounds.

The amount of the catalyst to be used is usually from 0.01 to 1 mole per1 mole of aldehyde.

The condensation reaction can be carried out in a known manner. Thecondensation reaction can be carried out at the temperature in the rangeof 60 to 120° C. for 2 to 30 hours. The condensation can be carried outin the presence of a solvent such as methyl ethyl ketone, methylisobutyl ketone and acetone. After condensation reaction, awater-insoluble solvent is added to the reaction mixture, as needed, thereaction mixture is washed with water, and then concentrated, wherebycollecting a novolak resin.

The weight average molecular weight of the novolak resin is preferably3,000 to 10,000, more preferably 6,000 to 9,000 and still morepreferably 7,000 to 8,000. When falling within these ranges, it ispossible to effectively prevent the thinning film and the remainingresidues after development.

The resin having polymerization unit derived from a hydroxystylene istypically polyvinylphenol, and preferably poly-p-vinylphenol, such as aresin having the structural unit (a2-1). The polyvinylphenol can beobtained by polymerization of monomers described in JP2010-204634A1.

The resin having polymerization unit derived from a (meth)acrylic acidcan be obtained by a known polymerization of the following ones asmonomers, which may be used as a single monomer or as a combination oftwo or more monomers;

monomer having a carboxy group such as (meth)acrylic acid;

monomer having a hydroxy group such as 2-hydroxyethyl(meth)acrylate,2-hydroxypropyl (meth) acrylate;

monomer having multiple ether bonds, polyethylene glycol monomethylether (meth)aclylates such as diethylene glycol monomethyl ether(meth)acrylate, triethylene glycol monomethyl ether (meth)acrylate,tetraethylene glycol monomethyl ether (meth)acrylate, pentaethyleneglycol monomethyl ether (meth)acrylates, hexa ethylene glycol monomethylether (meth)acrylate, heptaethylene glycol monomethyl ether(meth)acrylate, octaethylene glycol monomethyl ether (meth)acrylate,nonaethylene glycol monomethyl ether (meth acrylate.

The above monomers may be used in combination with the following ones;

(meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl(meth)acrylate, tert-butyl (meth)acrylate;

(meth) acrylic acid cycloalkyl esters such as cyclopentyl (meth)acrylate, cyclohexyl (meth) acrylate;

polycyclic (meth)acrylic acid esters such as adamantyl (meth)acrylate;

ethylene glycol monoalkyl ether (meth)acrylates such as ethylene glycolmonomethyl ether (meth)acrylate, ethylene glycol monoethyl ether(meth)acrylate, ethylene glycol monopropyl ether (meth)acrylate,ethylene glycol monobutyl ether (meth)acrylate.

The content of the resin (A2) in the resist composition is preferably10% by mass or more, and more preferably 20% by mass or more, andpreferably 70% by mass or less, and more preferably 65% by mass or lesswith respect to the total amount of the resin contained in the resistcomposition.

<Acid Generator (B)>

The resist composition of the disclosure contains an acid generator (B).

The acid generator is a compound which can be decomposed by light togenerate an acid. The acid acts catalytically to the resin (A) andeliminate a leaving group which is detached by contacting with an acidfrom the resin (A). The acid generators may be either ionic or non-ionicone.

Examples of the non-ionic acid generator include organic halide,sulfonate esters (e.g., 2-nitrobenzoate, aromatic sulfonate, oximesulfonate, N-sulfonyloxyimide, sulfonyl oxyketone, diazonaphthoquinone4-sulfonate) and sulfone (e.g., disulfone, ketosulfone,sulfonyldiazomethane). Examples of the ionic acid generator include anonium salt containing an onium cation (e.g., adiazonium salt, aphosphonium salt, a sulfonium salt, an iodonium salt). Examples of ananions of the onium salts include a sulfonic acid anion, a sulfonylimideanion and a sulfonylmethide anion.

The acid generator includes compounds which generate an acid uponradiation, which are described in JP63-26653A1, JP 55-164824A1,JP62-69263A1, JP63-146038A1, JP63-163452A1, JP 62-153853A1,JP63-146029A1, U.S. Pat. No. 3,779,778, U.S. Pat. No. 3,849,137, Germanpatent No. 3914407 and European patent No. 126712. The acid generator isavailable on the market, or it can be prepared by a known method.

The non-ionic acid generator is preferably a compound which has a grouprepresented by formula (B1):

wherein R^(b1) represents a C₁ to C₁₈ hydrocarbon group that may have afluorine atom, and a methylene group contained in the hydrocarbon groupmay be replaced by an oxygen atom or a carbonyl group.

The nitrogen atom in formula (B1) may have a double bond, although it isnot illustrated therein.

The C₁ to C₁₈ hydrocarbon group may be an aliphatic hydrocarbon group,an alicyclic hydrocarbon group, an aromatic hydrocarbon group and acombination thereof.

Examples of the aliphatic hydrocarbon group include an alkyl groups suchas methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl octyl, nonyl anddecyl groups.

Examples of the alicyclic hydrocarbon group include cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl andadamantyl groups.

Examples of the aromatic hydrocarbon group include a C₆ to C₁₈ arylgroup such as phenyl, naphthyl, anthryl, p-methylphenyl,p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl,biphenyl, phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenylgroups.

The hydrocarbon group is preferably a C₁ to C₁₀ alkyl group or a C₆ toC₁₀ aromatic hydrocarbon group, and more preferably a C₁ to C₈ alkylgroup, and still more preferably a C₁ to C₄ alkyl group.

Examples of the hydrocarbon group in which a methylene group is replacedby an oxygen atom or a carbonyl group includes those represented byformulae (Y1) to (Y12), preferably those represented by formulae (Y7) to(Y9), more preferably one represented by formula (Y9):

wherein “*” represents a binding position.

Examples of the hydrocarbon group which has a fluorine atom includefluoroalkyl groups such as fluoromethyl, fluoroethyl, fluoropropyl,fluorobutyl, fluoropentyl, fluorohexyl, fluoroheptyl, fluorooctyl,fluorononyl and fluorodecyl groups; alicyclic fluorohydrocarbon groupssuch as cyclofluoropropyl, cyclofluorobutyl, cyclofluoropentyl,cyclofluorohexyl, cyclofluoroheptyl, cycloperfluorooctyl andfluoroadamantyl groups; fluoroaryl groups such as fluorophenyl,fluoronaphthyl and fluoroanthryl groups.

The hydrocarbon group which has a fluorine atom is preferably a C₁ toC₁₀ alkyl group which has a fluorine atom and a C₆ to C₁₀ aromatichydrocarbon group which has a fluorine atom, and more preferably a C₁ toC₈ perfluoroalkyl group, and still more preferably a C₁ to C₄perfluoroalkyl group.

Examples of the compound represented by formula (B1) includes thecompounds represented by formulae (b1), (b2) and (b3), preferably thecompounds represented by formulae (b1) and (b2), more preferably thecompounds represented by formula (b1).

In the formulae, R^(b1) is as the defined above,

R^(b2′), R^(b3) and R^(b4) in each occurrence independently represent ahydrogen atom, a C₁ to C₈ alkyl group or a C₁ to C₈ alkoxy group, and

ring W^(b1) represents a C₆ to C₁₄ aromatic hydrocarbon ring or a C₆ toC₁₄ aromatic heterocyclic group; and

“x” represents an integer of 0 to 2.

Examples of the alkyl group include methyl, ethyl, propyl, butyl andpentyl groups, preferably a methyl group.

Examples of the alkoxy group include methoxy, ethoxy, propoxy, butoxy,and pentyloxy groups, preferably a methoxy group.

Examples of the aromatic hydrocarbon ring include benzene, naphthaleneand anthracene rings.

Examples of the aromatic heterocyclic group include a six-membered tofourteen-membered ring, which preferably includes the following ones:

Examples of the substituent which may bind to the ring W^(b1) includes aC₁ to C₅ alkyl group.

The ring W^(b1) is preferably a naphthalene ring.

The compound represented by formula (b1) is preferably a compoundrepresented by any one of formulae (b4) to (b7), more preferably acompound represented by formula (b4).

In the formulae,

R^(b1) is as defined above,

R^(b2), R^(b5), R^(b6) and R^(b7) each independently represent ahydrogen atom, or a C₁ to C₈ alkyl group.

Examples of the compound represented by formula (b ) include preferablythose represented by formulae (b1-1) to (b1-14), more preferably thoserepresented by formulae (b1-6) and (b1-7).

Examples of the compound represented by formula (b3) include thefollowing ones.

The ionic acid generator is preferably a compound represented by formula(b8) or (b9):

wherein A^(b1) and A each independently represent an oxygen atom or asulfur atom,

R^(b8), R^(b9), R^(b10) and R^(b11) each independently represent a C₁ toC₁₀ alkyl group or a C₆ to C₁₂ aromatic hydrocarbon group, and

X1⁻ and X2⁻ each independently represent an organic anion.

Examples of the alkyl group include methyl, ethyl, propyl, butyl,pentyl, hexyl, heptyl group and octyl groups.

Examples of the aromatic hydrocarbon groups include an aryl group suchas phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-buthylphenyl,p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl,phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.

R^(b8), R^(b9), R^(b10) and R^(b11) are each independently preferably aC₆ to C₁₂ aromatic hydrocarbon group, more preferably a phenyl group.

Examples of the organic anion for X1⁻ and X2⁻ include a sulfonic acidanion, a bis(alkylsulfonyl)amide anion and a tris(alkylsulfonyl) methideanion. The sulfonic acid anion is preferred, and the sulfonic acid anionrepresented by formula (b10) is more preferred.

In the formula,

R^(b12) represents a C₁ to C₁₈ hydrocarbon group that may have afluorine atom, and a methylene group contained in the hydrocarbon groupmay be replaced by an oxygen atom or a carbonyl group.

Examples of R^(b12) include the same ones as the group of R^(b1).

Examples of the compound represented by formula (b9) include thefollowing ones.

Examples of the compound represented by formula (b10) include thefollowing ones.

As the acid generator (B), a single salt or a mixture of two or more ofthe salts can be used.

The content of the acid generator (B) is preferably 0.3 parts by mass ormore, preferably 0.5 parts by mass or more, and more preferably 1 partsby mass or more, and preferably 30 parts by mass or less, morepreferably 10 parts by mass or less, and still more preferably 5 partsby mass or less, with respect to 100 parts by mass of the resin (A).

<Solvent (D)>

There is no particular limitation on the solvent (D) as along as itdissolves the components contained in the resist composition of thedisclosure, examples of the solvent includes a glycol ether ester suchas ethyl cellosolve acetate, methyl cellosolve acetate and propyleneglycol monomethyl ether acetate; a glycol ether such as propylene glycolmonomethyl ether; an ester such as ethyl lactate, butyl acetate, amylacetate and ethyl pyruvate; a ketone such as acetone, methyl isobutylketone, 2-heptanone and cyclohexanone; a lactone such asγ-butyrolactone; and a combination thereof.

The content of the solvent is usually 40 to 75% by mass, preferably 45to 70% by mass, and more preferably 50 to 68% by mass with respect tototal amount of the resist composition of the disclosure. With thisrange, the resist composition layer having a thickness of about 3 to 150μm can easily be formed when producing a resist pattern.

<Quencher (C)>

The resist composition of the disclosure preferably further contains aquencher.

The quencher is a compound having a property trapping an acid generatedfrom the acid generator by exposure of light. Examples of the quencherinclude a basic nitrogen-containing organic compound.

Examples of the basic nitrogen-containing organic compound include anamine compound such as an aliphatic amine and an aromatic amine, and anammonium salt. Examples of the aliphatic amine include a primary amine,a secondary amine and a tertiary amine.

Examples of amine compounds include those represented by the formulae(C1) and (C2).

In the formula, R^(c1), R^(c2) and R^(c3) each independently represent ahydrogen atom, a C₁ to C₆ alkyl group, a C₅ to C₁₀ alicyclic hydrocarbongroup or a C₆ to C₁₀ aromatic hydrocarbon group, and a hydrogen atomcontained in the alkyl group and the alicyclic hydrocarbon group may bereplaced by a hydroxy group, an amino group or a C₁ to C₆ alkoxy group,and a hydrogen atom contained in the aromatic hydrocarbon group may bereplaced by a C₁ to C₆ alkyl group, a C₁ to C₆ alkoxy group or a C₅ toC₁₀ alicyclic hydrocarbon group.

Examples of the alkyl group, the alicyclic hydrocarbon group, thearomatic hydrocarbon group, an alkoxy group and an alkanediyl groupinclude the same examples as the group described above.

Examples of the compound represented by the formula (C1) include1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline,2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline,N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine,heptylamine, octylamine, nonylamine, decylamine, dibutylamine,dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine,didecylamine, triethylamine, trimethylamine, tripropylamine,tributylamine, tripentylamine, trihexylamine, triheptylamine,trioctylamine, trinonylamine, tridecylamine, dibutylmethylamine,methyldipentylamine, dihexylmethylamine, dicyclohexylmethylamine,diheptylmethylamine, methyldioctylamine, methyldinonylamine,didecylmethylamine, ethyldibutylamine, ethyldipentylamine,ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine,ethyldinonylamine, ethyldidecylamine,tris[2-(2-methoxyethoxyl)ethyl]amine, triisopropanolamine,ethylenediamine, tetramethylenediamine, hexamethylenediamine,4,4′-diamino-1,2-diphenylethane,4,4′-diamino-3,3′-dimethyldiphenylmethane and4,4′-diamino-3,3′-diethyldiphenylmethane. Among them, preferred isdiisopropylaniline, and more preferred is 2,6-diisopropylaniline.

In the formula, the ring W¹ represents a nitrogen-containingheterocyclic ring, or a benzene ring having a substituted orunsubstituted amino group, and a hydrogen atom contained in theheterocyclic ring and benzene ring may be replaced by a hydroxy group ora C₁ to C₄ alkyl group;

A¹ represents a phenyl group or a naphthyl group, and

“nc” represents an integer of 2 or 3.

The substituted or unsubstituted amino group is represented by—N(R^(c4))(R^(c5)), where R^(c4) and R^(c5) each independently representa hydrogen atom, a C₁ to C₁₀ aliphatic hydrocarbon group, a C₃ to C₁₀alicyclic hydrocarbon group or a C₆ to C₁₄ aromatic hydrocarbon group.

Examples of the aliphatic hydrocarbon group include an alkyl group suchas methyl, ethyl, n-propyl, isopropyl, n-butyl, butyl, pentyl, hexyl,heptyl and octyl groups.

Examples of the alicyclic hydrocarbon group include the same examples asthe group described for R^(a1), R^(a2) and R^(a3) in the formula (1),and examples of the aromatic hydrocarbon group include the same examplesas the group described for R^(a1′), R^(a2′) and R^(a3′) in the formula(2), described above.

The nitrogen-containing heterocyclic ring is an aromatic or non-aromaticring, or a ring having a hetero atom other than a nitrogen atom such asan oxygen atom and a sulfur atom. The hetero ring may have 1 to 3nitrogen atom(s). Examples of the hetero ring include a ring representedby any one of formulae (Y13) to (Y28). In each ring of the formulae, theposition where one hydrogen atom has been removed therefrom is a bindingposition to A¹.

The ring W¹ is preferably a nitrogen-containing heterocyclic ring, morepreferably a5- or 6-membered aromatic heterocyclic ring having anitrogen atom in its ring, and still more preferably a ring representedby any one of formulae (Y20) to (Y25).

The compound represented by formula (C2) includes those represented byformulae (C2-1) to (C2-11), preferably those represented by formulae(C2-2) to (C2-8).

The content of the quencher is preferably 0.0001 to 5% by mass, morepreferably 0.0001 to 4% by mass, still more preferably 0.001 to 3% bymass, further still preferably 0.01 to 1.0% by mass, and particularlypreferably 0.1 to 0.70% by mass with respect to the total amount ofsolid components of the resist composition.

<Adhesion Improver (E)>

There is no particular limitation on the adhesion improver (E) as alongas corrosion of a metal such as aluminum and copper used in a substrate,wiring, or the like can be prevented. An effect of preventing rusting isexhibited by prevention of corrosion of the metal. Furthermore, inaddition to those effects, it is possible to enhance the adhesivecharacteristics between the resist composition and the substrate or themetal.

The adhesion improver (E) may include a sulfur-containing compound, anaromatic hydroxyl compound, a benzotriazol compound, a triazine compoundand a silicon-containing compound. These may be used as a singlecompound or as a combination of two or more compounds.

The sulfur-containing compound may include a compound that has a sulfidebond and/or a mercapto group. The sulfur-containing compound may be achain compound or a compound having a ring structure.

Examples of the chain compound include dithiodiglycolic glycerol[S(CH₂CH(OH)CH₂(OH))₂], bis (2,3-dihydroxypropylthio)ethylene [CH₂CH₂(SCH₂CH(OH)CH₂(OH))₂],3-(2,3-dihydroxypropylthio)-2-methyl-propylsulfonic acid sodium salt[CH₂(OH)CH(OH)CH₂SCH₂CH(CH₃)CH₂SO₃Na], 1-thioglycerol[HSCH₂CH(OH)CH₂(OH)], 3-mercapto-1-propanesulfonic acid sodium salt[HSCH₂CH₂CH₂SO₃Na], 2-mercaptoethanol [HSCH₂CH₂(OH)], thioglycolic acid[HSCH₂CO₂H], 3-mercapto-1-propanol [HSCH₂CH₂CH₂].

The sulfur-containing compound is preferably a compound that has asulfide bond and a mercapto group, more preferably a heterocycliccompound that has a sulfide bond and a mercapto group. There is noparticular limitation on how many sulfide bonds and mercapto groups arepresented in the sulfur-containing compound, as long as both of thesegroups are presented respectively therein.

The heterocyclic ring may be a monocyclic or a polycyclic ring, and thering may be a saturated or an unsaturated ring. The heterocyclic ringpreferably has a hetero atom other than a sulfur atom. Examples of thehetero atom include an oxygen atom and a nitrogen atom, and preferably anitrogen atom.

The heterocyclic ring has preferably 2 to 12 carbon atoms, morepreferably 2 to 6 carbon atoms.

The heterocyclic ring is preferably a monocyclic ring or an unsaturatedring, and more preferably a monocyclic unsaturated ring.

Examples of the heterocyclic ring include the following ones.

The sulfur-containing compound may be a polymer. The polymer preferablyhas a structural unit which has a sulfide bond and a mercapto group inits side chain. A structure having a sulfide bond and a mercapto group(which is sometimes referred to as “unit (1)”) and a main chain arepreferably bonded together with a linking group such as an amido bond,an ether bond, a thioether bond and ester bond.

The polymer may be a homopolymer or a copolymer.

When the polymer is a copolymer, the copolymer may have the structuralunit (a1) and/or the structural unit (a2) described above.

The weight average molecular weight of the polymer is usually 3,000 ormore, preferably 5,000 or more, while it is usually 100,000 or less, andpreferably 50,000 or less.

When the sulfur-containing compound is a polymer, the content of thestructural unit which has a sulfide bond and a mercapto group is usually0.1 to 50% by mole, preferably 0.5 to 30% by mole, and more preferably 1to 20% by mole with respect to the total structural units of thepolymer.

The sulfur-containing compound is preferably a compound represented byformula (IA) or a polymer having a structural unit represented byformula (IB):

wherein R^(i1) represents a hydrogen atom, a C₁ to C₁₀ aliphatichydrocarbon group, a C₃ to C₁₈ alicyclic hydrocarbon group, a C₆ to C₁₄aromatic hydrocarbon group, —SR¹¹ or —N(R¹²)(R¹³);

R¹¹, R¹² and R¹³ each independently represent a hydrogen atom, a C₁ toC₁₀ aliphatic hydrocarbon group, a C₃ to C₁₀ alicyclic hydrocarbongroup, a C₆ to C₁₄ aromatic hydrocarbon group or a C₁ to C₁₂ acyl groupand a hydrogen atom contained in the aliphatic hydrocarbon group, thealicyclic hydrocarbon group, the aromatic hydrocarbon group or the acylgroup may be replaced by a hydroxy group;

R^(i2) and R^(i3) in each occurrence independently represent a hydrogenatom, a C₁ to C₁₀ aliphatic hydrocarbon group, a C₃ to C₁₈ alicyclichydrocarbon group or a C₆ to C₁₄ aromatic hydrocarbon group;

A and B each independently represent a nitrogen atom or a carbon atom;and

“n” and “m” each independently represent 0 or 1,

provided that n is 0 when A is a nitrogen atom, n is 1 when A is acarbon atom, m is 0 when B is a nitrogen atom, and m is 1 when B is acarbon atom.

Examples of the aliphatic hydrocarbon group include alkyl groups such asmethyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl and octyl groups.

Examples of the aromatic hydrocarbon group include an aryl group such asphenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl,p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl, biphenyl,phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl groups.

The alicyclic hydrocarbon group may be any one of a monocyclic orpolycyclic group, examples of the alicyclic hydrocarbon group include acycloalkyl group such as cyclopentyl, cyclohexyl, cycloheptyl andcyclooctyl group, and the polycyclic alicyclic hydrocarbon group such asdecahydronaphthyl, adamantyl and norbornyl groups.

R¹¹ is preferably an aliphatic hydrocarbon group or an acyl group, R¹²and R¹³ are each independently preferably a hydrogen atom, an aliphatichydrocarbon group, an aromatic hydrocarbon group or an acyl group.

Examples of the acyl group include acetyl, propionyl, butyryl, bareiru,hexylcarbonyl, heptylcarbonyl, octylcarbonyl, decylcarbonyl,dodecylcarbonyl and benzoyl groups.

R^(i1) is more preferably a hydrogen atom or a mercapto group.

R^(i2) and R^(i3) is each independently preferably a hydrogen atom or aC₁ to C₄ alkyl group, and more preferably a hydrogen atom.

At least one of A and B is preferably a nitro atom, and both of them aremore preferably nitrogen atoms.

In the formula, R^(i21) and R^(i31) in each occurrence independentlyrepresent a hydrogen atom, a C₁ to C₁₀ aliphatic hydrocarbon group, a C₃to C₁₈ alicyclic hydrocarbon group or a C₆ to C₁₄ aromatic hydrocarbongroup;

A¹ and B¹ each independently represent a nitrogen atom or a carbon atom;

R^(i4) represents a hydrogen atom or a methyl group;

X^(i1) represents a sulfur atom or a NH group;

L^(i1) represents a C₁ to C₂₀ divalent hydrocarbon group where amethylene group may be replaced by an oxygen atom or a carbonyl group;and

“n^(i)” and “m^(i)” each independently represent 0 or 1,

provided that n^(i) is 0 when A¹ is a nitrogen atom, n^(i) is 1 when A¹is a carbon atom, m^(i) is 0 when B¹ is a nitrogen atom, and m^(i) is 1when B¹ is a carbon atom.

Examples of aliphatic hydrocarbon group for R^(i21) and R^(i31) includealkyl groups such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyland octyl groups, preferably a C₁ to C₄ alkyl group.

Examples of the aromatic hydrocarbon group for R^(i21) and R^(i31)include an aryl group such as phenyl, naphthyl, anthryl, p-methylphenyl,p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl,biphenyl, phenanthryl, 2,6-diethylphenyl and 2-methyl-6-ethylphenylgroups, and preferably a C₆ to C₁₀ aryl group.

The alicyclic hydrocarbon group for R^(i21) and R^(i31) may be any oneof a monocyclic or polycyclic group, examples of the alicyclichydrocarbon group include a cycloalkyl group such as cyclopentyl,cyclohexyl, cycloheptyl and cyclooctyl group, and the polycyclicalicyclic hydrocarbon group such as decahydronaphthyl, adamantyl andnorbornyl groups, and preferably a C₅ to C₁₀ alicyclic hydrocarbongroup.

R^(i21) and R^(i31) are each independently preferably a hydrogen atom ora C₁ to C₄ alkyl group.

Examples of the divalent hydrocarbon group for L^(i1) include analkanediyl group such methylene, ethylene, propane-1,3-diyl,butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl,octane-1,8-iyl, nonane-1,9-diyl, decane-1,10-diyl, undecane-1,11-diyl,dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl,pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl,ethane-1,1-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-2,2-diyl,pentane-2,4-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl,pentane-1,4-diyl, 2-methylbutane-1,4-diyl;

a divalent monocyclic saturated alicyclic hydrocarbon group, i.e., acycloalkanediyl group such as cyclobutane-1,3-diyl,cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, cycloalkanediyl such ascyclooctane-1,5-diyl groups;

a divalent polycyclic saturated alicyclic hydrocarbon group such as anorbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl andadamantane-2,6-diyl groups;

an arylene group such as phenylene, tolylene and naphthylene groups.

L^(i1) is preferably a C₂ to C₁₄ alkanediyl group having an ester bondor a combination of a C₆ to C₁₀ arylene group with a C₁ to C₁₁alkanediyl group.

The structural unit represented by formula (IB) is preferably onerepresented by formula (IB-1) or formula (IB-2).

In the formulae, R^(i22) and R^(i32) each independently represent ahydrogen atom, a C₁ to C₁₀ aliphatic hydrocarbon group, a C₃ to C₁₈alicyclic hydrocarbon group or a C₆ to C₁₄ aromatic hydrocarbon group;

A² and B² each independently represent a nitrogen atom or a carbon atom;

R^(i5) represents a hydrogen atom or a methyl group;

X^(i11) represents a sulfur atom or an NH group;

L^(i2) represents a C₁ to C₁₈ divalent hydrocarbon group where amethylene group may be replaced by an oxygen atom or a carbonyl group,and

“n1” and “m1” each independently represent 0 or 1,

provided that “n1” is 0 when A² is a nitrogen atom, “n1” is 1 when A² isa carbon atom, “m1” is 0 when B² is a nitrogen atom and “m1” is 1 whenB² is a carbon atom;

R^(i23) and R^(i33) each independently represent a hydrogen atom, a C₁to C₁₀ aliphatic hydrocarbon group, a C₃ to C₁₈ alicyclic hydrocarbongroup or a C₆ to C₁₄ aromatic hydrocarbon group;

A³ and B³ each independently represent a nitrogen atom or a carbon atom;

R^(i7) represents a C₁ to C₆ alkyl group or a C₁ to C₆ alkoxy group;

X^(i12) represents a sulfur atom and an NH group;

L^(i3) represents a C₁ to C₁₄ divalent hydrocarbon group where amethylene group may be replaced by an oxygen atom or a carbonyl group;and

“n2” and “m2” each independently represent 0 or 1,

provided that “n2” is 0 when A³ is a nitrogen atom, “n2” is 1 when A³ isa carbon atom, “m2” is 0 when B³ is a nitrogen atom, and/or “m2” is 1when B³ is a carbon atom.

Examples of the C₁ to C₁₀ aliphatic hydrocarbon group for R^(i22),R^(i32), R^(i23) and R^(i33) each independently include the same ones asthe group of R^(i21) and R^(i31).

Examples of the C₆ to C₁₄ aromatic hydrocarbon group for R^(i22),R^(i32), R^(i23) and R^(i33) each independently include the same ones asthe group of R^(i21) and R^(i31).

Examples of the C₃ to C₁₈ alicyclic hydrocarbon group for R^(i22),R^(i32), R^(i23) and R^(i33) each independently include the same ones asthe group of R^(i21) and R^(i31).

Examples of the C₁ to C₁₈ divalent hydrocarbon group for L^(i2) includean alkanediyl group such as methylene, ethylene, propane-1,3-diyl,butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl,octane-1,8-diyl, nonane-1,9-diy, decane-1,10-diyl, undecane-1,11-diyl,dodecane-1,12-diyl, tridecane-1,13-diyl, tetradecane-1,14-diyl,pentadecane-1,15-diyl, hexadecane-1,16-diyl, heptadecane-1,17-diyl,ethane-1,1-diyl, propane-1,1-diyl, propane-1,2-diyl, propane-2,2-diyl,pentane-2,4-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl,pentane-1,4-diyl and 2-methylbutane-1,4-diyl;

a divalent monocyclic saturated alicyclic hydrocarbon group, i.e.,cycloalkanediyl group such as cyclobutane-1,3-diyl,cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, cycloalkanediyl such ascyclooctane-1,5-diyl groups;

a divalent polycyclic saturated alicyclic hydrocarbon group such as anorbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl andadamantane-2,6-diyl groups.

L^(i2) is preferably a C₁ to C₁₄ alkanediyl group, and more preferably aC₁ to C₁₁ alkanediyl group.

Examples of the C₁ to C₁₄ divalent hydrocarbon group for L^(i3) includean alkanediyl group such as methylene, ethylene, propane-1,3-diyl,butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl,octane-1,8-diyl, nonane-1,9-diy, decane-1,10-diyl, undecane-1,11-diyl,dodecane-1,12-diyl, ethane-1,1-diyl, propane-1,1-diyl, propane-1,2-diyl,propane-2,2-diyl, pentane-2,4-diyl, 2-methylpropane-1,3-diyl, 2-methylpropane-1,2-diyl, pentane-1,4-diyl and 2-methyl butane-1,4-diyl;

a divalent monocyclic saturated alicyclic hydrocarbon group, i.e.,cycloalkanediyl group such as cyclobutane-1,3-diyl,cyclopentane-1,3-diyl, cyclohexane-1,4-diyl, cycloalkanediyl such ascyclooctane-1,5-diyl groups;

a divalent polycyclic saturated alicyclic hydrocarbon group such as anorbornane-1,4-diyl, norbornane-2,5-diyl, adamantane-1,5-diyl andadamantane-2,6-diyl groups.

L^(i3) is preferably a C₁ to C₁₄ alkanediyl group, and more preferably aC₁ to C₁₁ alkanediyl group.

L^(i3) is preferably bonded to a phenylene group so as to form apara-position with respect to a main chain.

Examples of the sulfur-containing compound include compounds representedby formulae (I-1) to (I-26), among them, those represented by formulae(I-1) to (I-13) are preferred, and those represented by formulae (I-1),(I-4) and (I-11) are more preferred.

Example for the sulfur-containing compound include a homopolymer and acopolymer which has at least one of the structural unit represented byany one of formulae (I-27) to (I-38), a copolymer which has at least oneof the structural unit represented by any one of formulae (I-27) to(I-36) are preferred, a copolymer which has the structural unitrepresented by formula (I-33) is more preferred.

Examples of such copolymer include a copolymer represented by formulae(I-39) to (I-48), and a copolymer represented by formulae (I-39) to(I-44) are preferred.

The sulfur-containing compound may be synthesized by a known method (forexample, these disclosed in JP2010-79081A1), or may be available producton the market. The polymer that is a sulfur-containing compound may beavailable product on the market (for example, bismuthiol, manufacturedby Tokyo Chemical Industry Co., Ltd.), or may be synthesized by a knownmethod (for example, that disclosed in JP2001-75277A1).

Examples of the aromatic hydroxy compound include phenol, cresol,xylenol, pyrocatechol (=1,2-dihydroxybenzene), tert-butyl catechol,resorcinol, hydroquinone, pyrogallol, 1,2,4-benzene triol, salicylalcohol, p-hydroxybenzyl alcohol, o-hydroxy benzyl alcohol, p-hydroxyphenethyl alcohol, p-aminophenol, m-aminophenol, diaminophenol, aminoresorcinol, p-hydroxybenzoic acid, o-hydroxybenzoic acid,2,4-dihydroxybenzoic acid, 2,5-dihydroxybenzoic benzoic acid,3,4-dihydroxybenzoic acid, 3,5-dihydroxybenzoic acid and gallic acid.

Examples of the benzotriazole compound include a compound represented byformula (IX):

wherein R¹ and R² each independently represent a hydrogen atom, anoptionally substituted C₁ to C₁₀ hydrocarbon group, a carboxyl group, anamino group, a hydroxyl group, a cyano group, a formyl group, a sulfonylalkyl group or a sulfone group.

Q represents a hydrogen atom, a hydroxyl group, an optionallysubstituted C₁ to C₁₀ hydrocarbon group, an aryl group or**—R³—N(R⁴)—R⁵, the hydrocarbon group may has an amide bond or an esterbond,

R³ represents an alkanediyl group,

** represents a binding position with a nitrogen atom included the ring,and

R⁴ and R⁵ each independently represent a hydrogen atom, a hydroxylgroup, a C₁ to C₆ alkyl group, a C₁ to C₆ hydroxyalkyl group or a C₁ toC₆ alkoxyalkyl group.

The hydrocarbon group for R¹, R² and Q may be an aliphatic hydrocarbongroup or an aromatic hydrocarbon group, and may have a saturated and/orunsaturated bond.

The aliphatic hydrocarbon group is preferably an alkyl group. Examplesof the alkyl group include methyl, ethyl, n propyl, isopropyl, n-butyl,sec-butyl, tert-butyl, n-pentyl, methylpentyl, n-hexyl and n-heptylgroups.

The aromatic hydrocarbon group is preferably an aryl group. Examples ofthe aryl group include phenyl, naphthyl, anthryl, p-methylphenyl,p-tert-butylphenyl, p-adamantyl-phenyl, tolyl, xylyl, cumenyl, mesityl,biphenyl, phenanthryl, 2, 6-diethylphenyl and 2-methyl-6-ethylphenylgroups.

Examples of the alkanediyl group for R³ include the same ones as thegroup described above.

Examples of the substituent for the hydrocarbon group include a hydroxylalkyl and an alkoxyalkyl groups.

Examples of the hydroxylalkyl group include hydroxymethyl andhydroxyethyl groups.

Examples of the alkoxyalkyl group include methoxymethyl, methoxyethyland dimethoxyethyl groups.

When the resist composition of the disclosure is applied to a substratethat includes copper layer, it is preferred to use a compound in which Qin formula (IX) is **—R³—N(R⁴)(R⁵). Among them, although thebenzotriazole compound in which Q is **—R³—N(R⁴)(R⁵) and at least one ofR⁴ and R⁵ is a C₁ to C₆ alkyl group exhibits reduced solubility in waterwhen at least one of R⁴ and R⁵ is a C₁ to C₆ alkyl group, the compoundis preferably used provided that another component capable of dissolvingthe compound is present therein.

When the resist composition of the disclosure is applied to a substratethat has an inorganic material layer (for example, polysilicon film andamorphous silicon film), Q in formula (IX) is preferably a water solublegroup, and more specifically a hydrogen atom, a C₁ to C₃ alkyl group, aC₁ to C₃ hydroxyalkyl group or a hydroxyl group. In this manner, theanticorrosive properties of the substrate are effectively exerted.

Examples of the benzotriazole compounds include benzotriazole,5,6-dimethyl benzotriazole, 1-hydroxybenzotriazole,1-methylbenzotriazole, 1-aminobenzotriazole, 1-phenylbenzotriazole,1-hydroxymethyl benzotriazole, 1-benzotriazole carboxylic acid methylester, 5-benzotriazole carboxylic acid, 1-methoxy-benzotriazole,1-(2,2-dihydroxy-ethyl)benzotriazole,1-(2,3-dihydroxypropyl)benzotriazole, or2,2′-{([(4-methyl-1H-benzotriazol-1-yl)methyl]imino}bisethanol,2,2′-{([(5-methyl-1H-benzotriazol-1-yl)methyl]imino}bisethanol,2,2′-{[(4-methyl-1H-benzotriazol-1-yl)methyl]imino}bisethane and2,2′-{[(4-methyl-1H-benzotriazole-1-yl) methyl]imino}bispropane whichare available on the market from Ciba Specialty Chemicals as “Irgamet”series.

Examples of the triazine compound include a compound represented byformula (II):

wherein R⁶, R⁷ and R⁸ each independently represent a halogen atom, ahydrogen atom, a hydroxy group, an amino group, a mercapto group, anoptionally substituted C₁ to C₁₀ hydrocarbon group, an optionallysubstituted C₁ to C₁₀ alkoxy group or an amino group substituted with aC₁ to C₁₀ hydrocarbon group.

Examples of the halogen atom include a fluorine, chlorine, bromine andiodine atoms.

Examples of the hydrocarbon group and an alkyl group include the sameones as the group described above.

Examples of triazine compounds include 1,3,5-triazine-2,4,6-trithiol.

Examples of the silicon-containing compound include a compoundrepresented by formula (IIA):

wherein R^(j1) represents a C₁ to C₅ aliphatic hydrocarbon group or a C₁to C₅ mercaptoalkyl group,

R^(j2) to R^(j4) each independently represent a C₁ to C₅ aliphatichydrocarbon group, a C₁ to C₅ alkoxy group, a mercapto group or a C₁ toC₅ mercaptoalkyl group, at least one of R^(j2) to R^(j4) is amercaptoalkyl group or a C₁ to C₅ mercapto group, and

t^(i) represents an integer of 1 to 10.

Examples of the aliphatic hydrocarbon group include an alkyl group suchas methyl, ethyl, propyl butyl and pentyl groups Examples of the alkoxygroup include methoxy and ethoxy groups.

Examples of the mercapto alkyl group include methylmercapto,entylmercapto and puropylmercapto groups.

R^(j1) is preferably a C₁ or C₂ aliphatic hydrocarbon group and a C₁ toC₃ mercaptoalkyl group, and more preferably a methyl group or amercaptopropyl group.

R^(j2) to R^(j4) are each independently preferably a C₁ or C₂ aliphatichydrocarbon group, a C₁ or C₂ alkoxy group, and more preferably a methylgroup and a methoxy group. At least one of these is preferably amercapto group or a C₁ to C₃ mercaptoalkyl group, and more preferably amercapto group or a mercaptopropyl group.

R^(j2) and R^(j3) may be the same or different from each other, and arepreferably the same in view of productivity.

Examples of the compound represented by formula (IIA) include thecompounds represented by formula (II-1) to formula (II-7).

Among them, 3-mercaptopropyl trimethoxysilane and 3-mercaptopropyltriethoxysilane are preferred.

The content of the adhesion improver (E) is preferably 0.001% by mass ormore, more preferably 0.002% by mass or more, still more preferably0.005% by mass or more, especially preferably 0.008% by mass or more,and preferably 20 by mass % or less, more preferably 10% by mass orless, more preferably 4% by mass or less, still more preferably 3% bymass or less, especially preferably 1% by mass or less, more preferablyespecially 0.1% by mass or less, with respect to the total amount of thesolid content of the resist composition. The resist composition withinthis range can form a resist pattern with high accuracy, ensuring theadhesion between the resist pattern and the substrate.

<Other Component (which is Sometimes Referred to as “Other Component(F)”)>

The resist composition of the disclosure may contain other components,as needed. Examples of the other component (F) include various additivesknown in the art such as surfactants, sensitizers, dissolutioninhibitors, stabilizers and dyes.

When the other component (F) is used, the content may be adjusteddepending upon the kinds thereof.

<Preparing the Resist Composition>

The resist composition can usually be prepared by mixing the resin (A1),the resin (A3), the acid generator (B), the compound (I) and the solvent(D) as well as the resin (A2), the quencher (C), the adhesion improver(E) and/or other component (F), as needed.

There is no particular limitation on the order of mixing. Thetemperature of mixing may be adjusted within the range of 10 to 40° C.depending on the kinds of the resin and solubility to the solvent. Thetime of mixing may be adjusted within the range of 0.5 to 24 hoursdepending on temperature during mixing. There is no particularlimitation to the tool for mixing. An agitation mixing may be used.

After mixing the above components, the mixture is preferably filtratedthrough a filter having about 0.11 to 50 μm pore diameter.

<Method for Producing Resist Pattern>

The method for producing a resist pattern of the disclosure includes thesteps of:

(1) applying the resist composition of the disclosure onto a substrate;

(2) drying the applied composition to form a composition layer;

(3) exposing the composition layer; and

(4) developing the exposed composition layer.

In the step (1), the applying of the composition on a substrate isusually conducted using a conventional apparatus such as spin coater.Examples of the substrate include silicon wafers. A substrate on whichsemiconductor elements (e.g., a transistor, a diode) has been formed inadvance can be used for the process. When the resist composition is tobe used for bump formation, a substrate on which a conductive materialhas been laminated is preferred. Examples of the conductive materialinclude a metal such gold (Au), copper (Cu), nickel (Ni), tin (Sn),palladium (Pd), and silver (Ag), and an alloy which contains one or moreof these metals. Copper and an alloy containing copper are preferred.

The substrate may be washed or coated with an anti-reflecting layer. Forforming the anti-reflecting layer, a composition for an organicanti-reflecting layer as available on the market can be used.

In the step (2), the composition layer is usually formed on thesubstrate by drying the applied composition to remove the solventtherefrom. The drying is carried out with a heating apparatus such ashot plate (i.e., prebake) for a heat drying, a decompressor for adecompression drying, or a combination thereof.

The temperature is preferably 50 to 200° C., and the operation pressureis preferably 1 to 1.0×10⁵ Pa.

The thickness of the film obtained by step (2) is in the range ofpreferably 3 to 150 μm, more preferably 4 to 100 μm.

In the step (3), the film is preferably exposed to light using anexposure system. The exposure is usually carried out through a maskhaving a pattern corresponding to a desired resist pattern. The exposuresource can be selected depending on resolution of the intended resistpattern, examples of the exposure source preferably include known onesuch as a light source emitting a light of 345 to 436 nm of wavelengthor a light source emitting a light of 345 to 400 nm of wavelength, morepreferably g ray (wavelength: 436 nm), h ray (wavelength: 405 nm) and iray (wavelength: 365 nm).

The process may further has baking the exposed film, so calledpost-exposure bake, after the step (3), preferably heating with aheating apparatus. The baking the exposed film can be carried out withheating means such as hot plates. The temperature of baking the exposedfilm is preferably 50 to 200° C., and more preferably 60 to 120° C. Thetime of baking is usually 40 to 400 seconds, preferably 50 to 350seconds.

In the step (4), the development of the exposed resist composition layeris usually carried out. When heating has been carried out, thedevelopment of the baked resist composition layer is usually carriedout. An alkaline developer is usually used for the development.

Examples of the alkaline developer includes an aqueous solution oftetramethylammonium hydroxide or (2-hydroxyethyl)trimethylammoniumhydroxide (commonly known as “choline”).

After development, the formed resist pattern is preferably washed withultrapure water, and the remained water on the resist pattern and thesubstrate is preferably removed.

<Application>

The resist composition of the disclosure is useful for forming a thickfilm, in particular, for forming a resist film having 3 to 150 μm-thick

Further, the resist composition is useful for producing bumps. When thebump is formed using the resist composition, bumps can be produced bythe process including the following steps;

laminating a conductive material (seed metal) on a wafer which hassemiconductor elements thereon to form a conductive film,

producing a resist pattern on the conductive film from the compositionof the disclosure,

plating an electrode material such as Cu, Ni or solder, using the resistpattern as its mold, and

removing the resist film and the conductive film under the resist filmby etching or the like, whereby forming the bumps. The electrodematerial which has been melted by heating after removing the conductivefilm may be used as a bump, as needed.

The resist composition of the disclosure can provide a resist patternwith excellent shape, therefore it is useful for formation of the bumps.

Example

The disclosure will be described more specifically by way of examples,which are not construed to limit the scope of the disclosure.

All percentages and parts expressing the content or amounts used in theExamples and Comparative Examples are based on mass, unless otherwisespecified.

The weight average molecular weight is a value determined by gelpermeation chromatography.

Apparatus: HLC-8120GPC type (Tosoh Co. Ltd.)

Column: TSK gel Multipore HXL-M×3+guardcolumn (Tosoh Co. Ltd.)

Eluant: tetrahydrofuran

Flow rate: 1.0 mL/min

Detecting device: RI detector

Column temperature: 40° C.

Injection amount: 100 μL

Standard material for calculating molecular weight: standard polystyrene(Tosoh Co. ltd.)

Synthesis Example 1 Synthesis of Resin A1-1

20 parts of polyvinylphenol [VP-15000; manufactured by Nippon Soda] wasdissolved in 240 parts of methylisobutylketone and the obtained solutionwas concentrated using an evaporator. The concentrated resin solutionand 0.003 parts of p-toluenesulfonic acid dihydrate were charged into afour-necked flask provided with a reflux condenser tube, a stirrer and athermometer. The temperature was maintained at 20 to 25° C. and 5.05parts of ethyl vinyl ether was dropped over 10 minutes into theresulting mixture. The mixture was continuously stirred for two hourswhile maintaining the same temperature. The resulting reaction mixturewas diluted with 200 parts of methylisobutylketone, followed byconducting a step of washing with ion-exchanged water and separating anorganic layer therefrom five times. The resulting organic layer wasconcentrated to 45 parts using an evaporator, 150 parts of propyleneglycol monomethyl ether acetate were added and then concentration wascarried out to obtain 78 parts of a propylene glycol monomethyl etheracetate solution of resin A1-1 (solid component 29%). The weight averagemolecular weight of the resin A1-1 was 2.21×10⁴. In the resin, theintroduction rate of ethoxyethyl groups was 38.5% of the hydroxy groupson the phenol groups. The resin A1-1 had the structural units as shownbelow.

Synthesis Example 2 Synthesis of Resin A1-2

120 g of phenol novolak resin (PSM-4326 manufactured by Gun Ei ChemicalIndustry) was charged into a flask and dissolved in 960 g ofmethylisobutylketone. The obtained phenol novolak resin solution waswashed 5 times with ion-exchanged water. The resulting resin solutionwas concentrated to 327.3 g. The resin concentration of the resinsolution was 35.2%.

56.8 g of the resulting resin solution obtained above (unit molecularweight: 189 mmol), 76.52 g of methyl isobutyl ketone and 3.6 mg ofp-toluensulfonic acid hydrate (0.0189 mmol) were charged into a flask.6.54 g of ethyl vinyl ether (0.0907 mmol) was dropped into the resinsolution, and then reaction was conducted for three hours at roomtemperature. Then ion-exchanged water was added to the reaction solutionand stirred, and allowed to stand, followed by separating an organiclayer therefrom. Washing by use of the ion-exchanged water was conductedfour times, for the total of five times. Thereafter, the organic layerwas removed and concentrated. Then, propylene glycol monomethyl etheracetate was added thereto for azeotropic removal of the aqueous fractionand methyl isobutyl ketone, and then the obtained organic layer wasconcentrated to obtain 59.77 g of resin solution. The resulting liquidwas a solution of a resin in which the hydroxyl groups of the phenylnovolak resin had been partially 1-ethoxyethylated. When the resin wasanalyzed using ¹H-NMR, 36.3% of hydroxyl groups were found to have been1-ethoxyethylated. The concentration of the resin solution was measuredusing a dry mass reduction method and found to be 38.8%. The resin wasreferred to as resin A1-2. The weight average molecular weight of thenovolak resin A1-2 was 5.1×10³.

Synthesis Example 3 Synthesis of Novolak Resin A2-1

To a four-necked flask with a stirring device, a reflux condenser and athermometer, 413.5 parts of 2,5-xylenol, 103.4 parts of salicylaldehyde,20.1 parts of p-toluenesulfonic acid and 826.9 parts of methanol werepoured, the temperature is increased to a reflux state, and thetemperature maintained for 4 hours. After cooling, 1320 parts ofmethylisobutylketone were charged, and 1075 parts were distilled away atordinary pressure. Then 762.7 parts of m-cresol and 29.0 parts of2-tert-butyl-5-methylphenol were added thereto and the temperature wasincreased to 65° C. 678 parts of 37% formalin was dropped over 1.5 hourswhile the temperature was adjusted to 87° C. at the time of completionof it. The temperature maintained 87° C. for 10 hours and 1115 parts ofmethylisobutylketone were added thereto, followed by conducting a stepof washing with ion-exchanged water, followed by separating a resinsolution therefrom three times. To the resulting resin solution, 500parts of methylisobutylketone was added, and vacuum concentration wascarried out until the total amount reached 3435 parts. 3796 parts ofmethylisobutylketone and 4990 parts of n-heptane were added to theresulting resin solution, the temperature was increased to 60 T. Afterone hour stirring, separation was carried out, the lower layer, that wasresin solution, was diluted using 3500 parts of propylene glycolmonomethyl ether acetate, and concentrated to obtain 1690 parts of apropylene glycol monomethyl ether acetate solution of novolak resin A2-1(solid component 43%). The weight average molecular weight of the resinA2-1 was 7×10³.

Synthesis Example 4 Synthesis of Compound Represented by Formula (aa)

To a four-necked flask with a stirring device, a reflux condenser and athermometer, 100 parts of triethylene glycol monomethyl ether, 100 partsof triethylamine and 600 parts of chloroform were charged and stirred atroom temperature to be mixed. A Solution in which 143 parts ofp-toluenesulfonyl chloride was dissolved in 360 parts of chloroform wasdropped into the obtained reaction solution on an ice bath, and themixture was stirred for one day at room temperature. To the obtainedreaction solution, 288 parts of ion-exchanged water was added, followedby conducting a step of washing with ion-exchanged water and separatingan organic layer therefrom twice to obtain an organic layer. 288 partsof 1% solution of oxalic acid was added to the obtained organic layer,followed by conducting a step of washing with ion-exchanged water andseparating an organic layer therefrom twice. Further, 288 parts ofion-exchanged water was added to the obtained organic layer, followed byconducting a step of washing with ion-exchanged water, followed byseparating an organic layer therefrom twice. 9.6 parts of the activatedcarbon was added to the obtained organic layer, and then the mixture wasstirred and filtrated. The obtained filtrate was concentrated to 214parts. The obtained concentrate was purified with column chromatography[solvent: mixture of n-heptane and ethyl acetate (weight ratio 4/1), andconcentrated again, dried under reduced pressure to obtain 169 parts ofthe compound represented by formula (aa) (purity: 97%).

Synthesis Example 5 Synthesis of Resin A3-1

To a four-necked flask with a stirring device, a reflux condenser and athermometer, 26 parts of polyvinylphenol (Trade name VP-8000, Product ofNippon Soda Co., Ltd.), 25 parts of isopropyl alcohol, 3.3 parts ofsodium hydroxide and 100 parts of ion-exchanged water were poured, andstirred to make a solution. Then 17 parts of the compound represented byformula (aa) was added to the obtained solution and the temperature isincreased to 80° C., and stirred for 5 hours. After cooling to roomtemperature, 100 parts of methylisobutylketone and 50 parts of 10%aqueous solution of oxalic acid were added to the obtained solution,followed by conducting a step of washing with ion-exchanged water andseparating an organic layer therefrom. 50 parts of 10% aqueous solutionof oxalic acid was added to the obtained solution, followed byconducting a step of washing with ion-exchanged water and separating anorganic layer therefrom. 100 parts of methylisobutylketone and 50 partsof ion-exchanged water were added to the obtained organic layer,followed by adding 2.5 parts of methanol thereto, followed by conductinga step of washing with ion-exchanged water and separating an organiclayer therefrom eight times. The obtained organic layer was concentrateduntil its amount became 45 parts using an evaporator, and 156 parts ofpropyleneglycolmonomethylether acetate was added thereto, followed byconcentrating it to obtain 70 parts of propyleneglycolmonomethyletheracetate solution (39% of solid content) of resin A3-1. The weightaverage molecular weight of the resin was 1.50×10⁴. In the resin, theintroduction rate of protective group was 21.2% of the hydroxy groups onthe phenol groups. Resin A3-1 had the following structural units.

Synthesis Example 6 Synthesis of Resin A3-2

To a four-necked flask with a stirring device, a reflux condenser and athermometer, 26 parts of polyvinylphenol (Trade name VP-8000, Product ofNippon Soda Co., Ltd.), 25 parts of isopropyl alcohol, 3.3 parts ofsodium hydroxide and 100 parts of ion-exchanged water were poured andstirred to make a solution. 10.18 parts of the compound represented byformula (aa) was added to the obtained solution and the temperature isincreased to 80° C., and stirred for 5 hours. After cooling to roomtemperature, 100 parts of methylisobutylketone and 50 parts of 10%aqueous solution of oxalic acid were added in this order to the obtainedsolution, followed by conducting a step of washing with ion-exchangedwater and separating an organic layer therefrom. 50 parts of 2% aqueoussolution of oxalic acid was added to the obtained solution, followed byconducting a step of washing with ion-exchanged water and separating anorganic layer therefrom. 100 parts of methylisobutylketone, 50 parts ofion-exchanged water and 2.5 parts of methanol were added to the obtainedorganic layer to separately-wash eight times. The obtained organic layerwas concentrated until its amount became 82 parts using an evaporator,and 156 parts of propyleneglycolmonomethylether acetate was addedthereto, followed by concentrating it again to obtain 67 parts ofpropyleneglycolmonomethylether acetate solution (41% of solid content)of resin A3-2. The weight average molecular weight of the resin was1.43×10⁴. In the resin, the introduction rate of protective group was13.2% of the hydroxy groups on the phenol groups. Resin A3-2 had thefollowing structural units.

Synthesis Example 7 Synthesis of Compound Represented by Formula (Ab)

To a four-necked flask with a stirring device, a reflux condenser and athermometer, 50 parts of diethylene glycol monovinyl ether, 2.3 parts ofN,N-dimethyl amino pyridine and 250 parts of pyridine were charged andstirred at room temperature to make a solution. 77 parts of aceticanhydride was dropped into the obtained solution, and the mixture wasstirred for 5 hours at room temperature. Then 250 parts of saturatedsodium hydrogen carbonate aqueous solution was added to the obtainedreaction solution, and 250 parts of ethyl acetate was added, followed byextracting the layer of the product compound. To the obtained aqueouslayer, 250 parts of ethyl acetate was added, followed by extracting thelayer of the product compound. Further, 250 parts of 10% of coppersulfate aqueous solution was added to the obtained organic layer [thelayer of the product], followed by conducting a step of washing withion-exchanged water and separating an organic layer therefrom. 250 partsof ion-exchanged water was added to the obtained organic layer, followedby conducting a step of washing with ion-exchanged water and separatingan organic layer therefrom four times. Toluene was added to the obtainedorganic layer and then concentrated until pyridine had been eliminatedto obtain 56 parts of the compound represented by formula (ab) (purity:100%).

Synthesis Example 8 Synthesis of Resin A3-3

128 parts of polyvinylphenol [VP-8000; manufactured by Nippon Soda], 128parts of p-toluenesulfonic acid monohydrate were dissolved in 403 partsof methylisobutylketone, and the obtained solution was concentratedusing an evaporator. To a four-necked flask with a stirring device, areflux condenser and a thermometer, the obtained concentrate was poured,18.4 parts of the compound represented by formula (ab) was added whilekeeping at 20 to 25° C. The mixture was stirred for 3 hours keeping thesame temperature, diluted with 10 parts of methyisobutylketone. Thereto60 parts of ion-exchanged water and 0.1 parts of triethylamine wasadded, followed by conducting a step of washing with ion-exchanged waterand separating an organic layer therefrom twice. To the obtainedsolution 60 parts of ion-exchanged water was added, followed byconducting a step of washing with ion-exchanged water and separating anorganic layer therefrom. The obtained organic layer was concentrateduntil its amount became 111 parts using an evaporator, and 311 parts ofpropyleneglycolmonomethylether acetate was added thereto, followed byconcentrating it to obtain 107 parts of propyleneglycolmonomethyletheracetate solution (49% of solid content) of resin A3-3. The weightaverage molecular weight of the resin was 1.66×10⁴. In the resin, theintroduction rate of protective group was 23.0% of the hydroxy groups onthe phenol groups. Resin A3-3 had the following structural units.

Examples 1 to 6 and Comparative Example 1 Preparing Resist Compositions

Resist compositions were prepared by mixing and dissolving each of thecomponents (parts) shown in Table 1, and then filtrating through afluororesin filter having 5.0 μm pore diameter.

TABLE 1 Acid Adhesion Resin Generator Quencher Improver PB/PEB Ex. 1A1-1 = 7.425, B1 = 0.24 C1 = 0.051 E1 = 0.01 110° C./— A2-1 = 4.725,A3-1 = 1.350 Ex. 2 A1-1 = 7.425, B1 = 0.24 C1 = 0.051 E1 = 0.01 110°C./— A2-1 = 4.725, A3-2 = 1.350 Ex. 3 A1-1 = 7.425, B1 = 0.24 C1 = 0.051E1 = 0.01 110° C./— A2-1 = 4.725, A3-3 = 1.350 Ex. 4 A1-1 = 7.425, B2 =0.23 C1 = 0.051 E1 = 0.01 110° C./— A2-1 = 4.725, A3-3 = 1.350 Ex. 5A1-1 = 7.425, B3 = 0.24 C1 = 0.051 E1 = 0.01 110° C./— A2-1 = 4.725,A3-3 = 1.350 Ex. 6 A1-2 = 7.425, B1 = 0.24 C1 = 0.051 E1 = 0.01 110°C./— A2-1 = 4.725, A3-3 = 1.350 Comp. A1-1 = 7.425, B1 = 0.24 C1 = 0.051E1 = 0.01 110° C./— Ex. 1 A2-1 = 5.400

The above resist compositions of Examples and Comparative Examplesfurther contain 0.002 parts of polyether modified silicone oil (Toraysilicone SH8400; Product of Toray Dow Corning, Co., Ltd.) as asurfactant

<Resin>

A1-1: Resin A1-1

A1-2: Resin A1-2

A2-1: Novolak Resin A2-1

A3-1: Resin A3-1

A3-2: Resin A3-2

A3-3: Resin A3-3

<Acid Generator>

B1: N-hydroxynaphthalimide triflate, trade name “NAI-105”, product byMidori Kagaku, Co., Ltd.

B2: The following compound, PAI-101 product by Midori Kagaku, Co., Ltd.

B3: The following compound, PAG-103 product by BASF

<Quencher>

C1: 2,4,5-triphenylimidazole (Product of Tokyo Chemical Industry, Co.,Ltd.)

<Adhesion Improver (E)>

E1: Bismuthiol (Product of Tokyo Chemical Industry, Co., Ltd.)

<Solvent>

Propyleneglycolmonomethylether acetate 21 parts

<Preparation of Resist Pattern>

On a 4-inches substrate where copper had been vapor-deposited on asilicon wafer, each of the resist compositions prepared as above wasspin-coated so that the thickness of the resulting film became 10 μmafter pre-baking.

Then the substrate was subjected to pre-baking on direct hotplate at thetemperature as shown in the column “PB” of Table 1 for 180 seconds.

Using an i-ray stepper (“NSR 1755i7A” manufactured by Nikon, NA=0.5) anda mask for forming a line and space pattern with line width andpitch=1:1 (the width thereof 5 μm), each wafer thus formed with therespective film was subjected to exposure with the exposure quantitybeing varied stepwise.

After exposure, each wafer was subjected to post-exposure baking on ahotplate at the temperature as shown in the columns “PEB” of Table 1 for60 seconds.

After that, each wafer was subjected to paddle development for 60seconds with an aqueous solution of 2.38% by mass tetramethylammoniumhydroxide to obtain resist patterns.

The Effective Sensitivity (ES) means the exposure quantity that the lineand space patterns became patterns with the width thereof 5 μm. Eachpattern was checked using a scanning microscope.

Shape:

The resist patterns with the line width thereof 5 μm were obtained byway of the process where the exposure was carried out at the exposurequantity of ES, and then each pattern was observed with a scanningelectron microscope at 2000-fold magnification. When the profile ofpattern was rectangle at both top and bottom sites as shown in FIG.1(a), it was marked by “∘” (good). When the profile of pattern was around shape at its top site as shown in FIG. 1(b), it was marked by “X”(bad).

Crack Resistance Evaluation:

On a 4-inches silicon wafer, each of the resist compositions wasspin-coated so that the thickness of the resulting film became 10 nmafter pre-baking. Then the wafer was subjected to pre-baking on directhotplate at the temperature as shown in the column “PB” of Table 1 for180 seconds. The obtained wafer was subjected to baking on a hotplate at130° C. for 5 minutes, and then cooled rapidly, followed by checking theobtained films with visual observation. Those wafers which had no crackon the film were marked by “∘∘” (excellent), those wafers which had oneto ten cracks were marked by “circle” (∘), single circle, and thosewafers which had ten or more cracks were marked by “X” (bad).

The results of the evaluation are listed in Table 2.

TABLE 2 Shape Crack Resistance Ex. 1 ∘(a) ∘ Ex. 2 ∘(a) ∘ Ex. 3 ∘(a) ∘∘Ex. 4 ∘(a) ∘ Ex. 5 ∘(a) ∘ Ex. 6 ∘(a) ∘∘ Comp. ∘(a) x Ex. 1

The resist composition of the disclosure can provide a resist patternshowing excellent shape and crack resistance.

The present resist composition can be used for semiconductormicrofabrication with resist patterns showing excellent shape.

What is claimed is:
 1. A resist composition comprising: a resin havingan acid-labile group, a resin having a structural unit represented byformula (I), an acid generator, and a solvent:

wherein R^(i41) represents a hydrogen atom or a methyl group, R^(i42)represents a C₂ to C₇ acyl group or a hydrogen atom, or a C₁ to C₁₀hydrocarbon group in which a hydrogen atom can be replaced by a hydroxygroup, R^(i43) in each occurrence independently represents a C₁ to C₆alkyl group or a C₁ to C₆ alkoxy group, “p” represents an integer of 0to 4, Z represents a divalent C₃ to C₂₀ hydrocarbon group having a grouprepresented by formula (Ia), and a methylene group contained in thehydrocarbon group may be replaced by an oxygen atom, a sulfur atom or acarbonyl group:*—[(CH₂)_(w)—O]_(r)—  (Ia) wherein “w” and “r” each independentlyrepresents an integer of 1 to 10, and * represent a bonding position,provided that R^(i42) represents a C₂ to C₇ acyl group when “w”represents
 1. 2. The resist composition according to claim 1 wherein thestructural unit represented by formula (I) is a structural unitrepresented by formula (I-1) or formula (I-2):

wherein R^(i41) represents a hydrogen atom or a methyl group, R^(i42)represents a C₁ to C₁₀ hydrocarbon group that may be substituted with ahydroxy group, a C₂ to C₇ acyl group or a hydrogen atom, R^(i43) in eachoccurrence independently represents a C₁ to C₆ alkyl group or a C₁ to C₆alkoxy group, “p” represents an integer of 0 to 4, R^(i44) represents aC₁ to C₁₀ hydrocarbon group, “r” represents an integer of 1 to 10, andR^(i45) represents a C₁ to C₁₀ hydrocarbon group that may be substitutedwith a hydroxy group, a C₂ to C₇ acyl group or a hydrogen atom.
 3. Theresist composition according to claim 1 wherein the resin having anacid-labile group is a resin having a structural unit represented byformula (a1-2):

wherein R^(a5) represents a hydrogen atom or a methyl group, R^(a1′) andR^(a2′) each independently represent a hydrogen atom or a C₁ to C₁₂hydrocarbon group, R^(a33′) represents a C₁ to C₂₀ hydrocarbon group, orR^(a1′) represents a hydrogen atom or a C₁ to C₁₂ hydrocarbon group, andR^(a2′) and R^(a33′) are bonded together with a carbon atom and anoxygen atom bonded thereto to form a divalent heterocyclic group having2 to 20 carbon atoms, and a methylene group contained in the hydrocarbongroup represented by R^(a1′) and R^(a2′) or the divalent heterocyclicgroup may be replaced by an oxygen atom or a sulfur atom, R^(a6) in eachoccurrence independently represents a C₁ to C₆ alkyl group or a C₁ to C₆alkoxy group, and “mz” represents an integer of 0 to
 4. 4. The resistcomposition according to claim 1 wherein the acid generator is acompound having a group represented by formula (B1):

wherein R^(b1) represents a C₁ to C₁₈ hydrocarbon group in which ahydrogen atom may have a fluorine atom and in which a methylene groupmay be replaced by an oxygen atom or a carbonyl group.
 5. A method forproducing a resist pattern comprising steps (1) to (4): (1) applying theresist composition according to claim 1 onto a substrate; (2) drying theapplied composition to form a composition layer; (3) exposing thecomposition layer; and (4) developing the exposed composition layer. 6.A resin comprising a structural unit represented by formula (I-2):

wherein R^(i41) represents a hydrogen atom or a methyl group, R^(i43) ineach occurrence independently represents a C₁ to C₆ alkyl group or a C₁to C₆ alkoxy group, “p” represents an integer of 0 to 4, R^(i44)represents a C₁ to C₁₀ hydrocarbon group, “r” represents an integer of 1to 10, and R^(i45) represents a C₁ to C₁₀ hydrocarbon group that may besubstituted with a hydroxy group, a C₂ to C₇ acyl group or a hydrogenatom.